God help me! Please god, if you have a heart, please help me. Me and my friends from hogwarts are trapped in the past, when Hogwarts wasn't even invented. God help us!!!!!

Rowena, Godric, Helga and Salazar get trapped in the past. They can't go to hogwarts because it's not invented yet! What will happen when they find a document and discover that they are supposed to invent it. How do they do that? That plus they're normal teenagers. Everyone here isn't quite as... modern here.